1 Field of the Invention
2 Description of Prior Art
In recent years, the flash apparatus has been widely employed in various kinds of optical apparatus which requires light of the flash. Particularly, in the art of photography, artificial light is used to illuminate an object to be photographed. One form of artificial light which has been in wide use is so-called electric flash device. In such devices, a flash tube is provided in order to illuminate the object to be photographed. The light from the flash tube can be used to illuminate the object to take a picture. Accordingly, the flash device is, mainly, used to take a picture at the night and to remove the unnecessary shadow of the object to be photographed under the natural light in the daytime.
The electric flash device comprises, mainly, a flashing member for generating and directing the flash light toward an object to be illuminated, a power source member for supplying the flashing energy to the flashing member, a charging member for storing the electric energy from the power source member and a flash control circuit member.
The flashing member is the most important part of the electric flash device, because it serves to focus and diffuse the flash light toward the luminous marks. The flashing member comprises a flash tube for generating the flash light, a reflector for focusing the flash light of the flash tube and a flash window for diffusing the flash light. The reflector is located behind the flash tube and the flash window is provided at the front of the reflector in order to diffuse and pass the flash light flux. The flash window is called a protecting plate, as it serves to protect the flash tube from the outer side of the reflector.
With the requirement for inserting the flash device into a camera the need for electric flash devices has rapidly increased. However it is always very difficult to make the electric flash device small without decreasing the output light thereof. Accordingly, efforts have been directed to reduce the size the electric flash device used in the camera.
To obtain an electric flash device conforming these conditions a necessarily complicated manufacturing process is required; and costs are commensurately unfavourable.
A conventional and prior art electric flash device is shown in FIGS. 1 to 3. A flashing member 20 is arranged on a front surface of a housing 10. Referring particularly to FIG. 2, the flashing member 20 comprises a reflector 30 for reflecting the flash light, a flash tube 40 for generating the flash light and positioned in the inner side of the reflector 30 and a flash window for diffusing the flash light from the flash tube 40. The flash tube 40 is constructed, mainly, by a cylindrical glass tube 41, a positive electrode 42 which is inserted in air-tight relationship into one end portion of the glass tube 41, a negative electrode 43 inserted in air-tight relationship and is opposed to the positive electrode 42, and a trigger electrode 44 which is provided on a circumferential surface of the glass tube 41.
In thus conventional electric flash device, a lead 45 is wound and fastened on the surface of the glass tube 41 in the vicinity of positive electrode 42 and, furthermore, a translucent conductive film is coated on the whole surface of the glass tube 41 so as to form the trigger electrode 44.
Furthermore, it is necessary to coat a silver paint after winding the lead 45 on the conductive film in order to make good electrical contact between the conductive film and the lead 45. It is, therefore, very troublesome to manufacture an electric flash device, because the coating of the film as well as the silver paint are required.